Nanoparticles wipe out filariasis mosquitoes

doi:10.1038/nindia.2016.3 Published online 12 January 2016

Researchers have discovered that
silver and carbon nanoparticles can separately kill the larvae and pupae of Culex quinquefasciatus — mosquitoes that
transmit lymphatic-filariasis-causing parasites to humans1. These
nanoparticles could potentially be useful for checking the spread of filariasis
in humans.

Lymphatic filariasis, also known
as elephantiasis, causes painful and disfiguring swelling of legs and genitalia,
and it afflicts millions in urban and semi-urban areas of Asia. Anti-filarial
drugs can treat the disease but are unable to cure chronic infection.

To find an alternative way to
combat lymphatic filariasis, the researchers converted silver nitrate solutions
into silver nanoparticles using seed extracts of a medicinal plant and also synthesized
carbon nanoparticles from citric acid and urea.

The silver and carbon
nanoparticles were found to be toxic to Cx.
quinquefasciatus larvae and
pupae. The
water bug Lethocerus indicus, which lives in the
same habitat as the mosquitoes, naturally devours the larvae and pupae.
Treating the water bug with the nanoparticles increased their efficiency in killing
the larvae and pupae.
The scientists found that low doses of the silver nanoparticles reduced the
motility of the mosquito larvae and pupae, allowing the water bug to devour
them more efficiently.

The nanoparticles did not detrimentally
affect the behaviour of other aquatic animals living in the same environment, suggesting
that they could be used to reduce the larval and pupal populations of filariasis-spreading
mosquitoes, the researchers say.